Grinding assembly for drill bits



3 y 2, 1956 c. K. JENSCH 2,746,212

GRINDING ASSEMBLY FOR DRILL. BITS Filed July 26, 1951 4 Sheets-Sheet 1J770ewz0r 1 C(yde Ji Jezasck May 22, 1956 c. K. JENSCH 2,746,212

GRINDING ASSEMBLY FOR DRILL BITS Filed July 26, 1951 4 Sheets-Sheet 2flizarrzeys May 22, 1956 c. K. JENSCH 2,746,212

GRINDING ASSEMBLY FOR DRILL BITS Filed July 26, 1951 4 Sheets-Sheet 3May 22, 1956 c. K. JENSCH GRINDING ASSEMBLY FOR DRILL BITS 4Sheets-Sheet 4 Filed July 26, 1951 I7? we)? 202 iiyde K Jeiasc5ifearzzqys United States Patent GRINDING ASSEMBLY non DRILL BrrS ClydeK. Jensch, Elm Grove, Wis, assignor to Nordberg Manufacturing Company,Milwaukee, Wis., 21 corpora tion of Wisconsin Application July 26, 1951,Serial No. 238,727

1 Claim. (Cl. 51-92) My invention relates to an improvement in toolsharpeners and has for one purpose to provide an apparatus upon whichtools or bits can be quickly and easily and accurately sharpened.

Another purpose is to provide a grinding assembly in which tools orelements to be faced or sharpened or surfaced are manually moved to apredetermined position or at a predetermined angle across the movingsurface of one or more grinding elements.

Another purpose is to provide a grinding assembly adapted for rapidgrinding or finishing of tools or bits where intersecting surfaces areto be ground.

Other purposes will appear from time to time in the course of thespecification and claim.

I illustrate the invention more or less diagrammatically in theaccompanying drawings, wherein:

Figure 1 is a perspective view of the assembly with certain of the partsremoved;

Figure 2 is a perspective view from another point of observationillustrating the parts assembly with one alternative working part orcarriage in use;

Figure 3 is a partial plan view with parts in section;

Figure 4 is a plan view of a working attachment;

Figure 5 is a section on the line 5-5 of Figure 4;

Figure 6 is a section on the line 6-6 of Figure 4;

Figure 7 is a partial sectional view taken on the line 7-7 of Figure 3illustrating the working attachment of Figure 4 in place.

Figure 8 is a plan view of another working carrier or attachment;

Figure 9 is an end view of the structure of Figure 8;

Figure 10 is a section on the line 10-10 of Figure 9; and

Figure 11 illustrates a bit or tool to be sharpened.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings, I illustrate a base plate 1 which may, forexample, be mounted on or carried by a pair of transversely extendingtubes 2. Mounted on the base plate 1 is any suitable motor block 3, thedetails of which do not of themselves form part of the presentinvention. It will be understood that any suitable motor means may beemployed, but that I illustrate generally the gasoline engine 4, whichdrives a pulley 5, about which passes a belt 6. Likewise supported onthe base plate 1 is a support 7, from which upwardly extends a Y-shapedsupporting element 8, upon which is rotatably mounted a shaft or shafts9, with which are rotatable grinding wheels 10, 10', of which two areshown. The pulley ll, connected to the shaft or shafts 9, is driven bythe belt 6 whereby, in response to normal operation of the motor 4, thegrinding wheels 10, 10' are rotated at suitable speed. Each such wheelis shown as surrounded by a suitable guard 12, 12', these guards beingmounted on any suitable bases or supports 13, 13'.

The Y-shaped member 8 is shown as carrying or including two spacedsleeves 14, 14 adapted to receive the two rods 16, 16' of the supportingmember 15. The supporting member 15 may be held in adjusted position forassembly by set screws 17, 17 associated with the sleeves 14, 14. Themember, or support, or guide 15 is shown as having an outwardly spacedwall member or side member 18 which has exteriorly mounted on it rollers19 and 20 and carrying also the internally mounted roller 21. With theparts assembled as shown in Figure 2, the axes of the three rollers arehorizontal and the rollers have their peripheries extending to the sameheight or plane. They are adapted and positioned to support a groovedmember or tracked member, such as is indicated at 25, for horizontalmovement along a path across the grinding Wheel 10.

While I do not limit the structure herein shown to work with anyparticular cutting tools, it is particularly adapted to sharpen orservice cutters of the type illustrated, for example at 26, and shown inperspective in Figure 11, such cutter having longitudinal flanges 26a,26b, the two flanges being aligned along opposite sides of the cutter orbit.

In order to sharpen various faces of the bit 26, I illustrate twodifferent carriers. The carrier 25 is formed with an upper slot 25a,which receives the lower flange 26b in guiding relationship. As will beclear from Figure 4, the guiding slot is at an angle, so that the bitwill be beveled at one side of its cutting end if the carrier 25 istraversed across the path to which it is constrained by the rollers. Inthis operation the end of the bit engages and is ground by the peripheryof the grinding wheel 10, which operation is shown in Figure 2.

As will be seen in Figure 7, the carrier 25 has a bottom track channelindicated at 25b which receives the rollers 19 and 26. It has also aflat track flange 250, which rests upon the inner roller 21. Thus theoperator, when he has positioned the bit 26 as shown in dotted line inFigure 7 or as shown in full line in Figure 2, can traverse the bitacross the grinding wheel 10. As will be seen in Figure 7, the bit 26does not lie in a horizontal plane, but is slightly inclined. It will beunderstood that after one end bevel is cut, the operator can then turnthe bit up side down and cut the opposite bevel.

The bit can be adjustably positioned on the carrier 25, for example bythe adjusting screw 27, which is controlled by a knurled knob 27a, andpasses through any suitable split holding block 28 controlled by thelocking member 28a. Thus the operator can easily adjust the screw 27 andthen lock it in place by rotating the locking member 28a. Thus the toolsor bits may be cut to precisely the same length, as well as to preciselythe same angle, as the carrier 25 is traversed across the peripheralgrinding surface of the grinding disk 10.

In order to cut or form edges or cuts to complete the cutting edge ofthe tool, I provide a second carrier 30. It has at one side a channeledtrack 30a which rides on and is guided by the rollers 19 and 20, itbeing understood that an additional fiat track or bearing surface 30b isprovided, as shown in Figure 9, to ride on the roller 21. In otherwords, both carriers can readily manually be traversed through apredetermined uniform path, whereby the bit or tool is always presentedto the grinding wheel at a predetermined controlled angle.

The carrier 39 is shown as including the guide flange 31 with a planeguiding surface 31a broken by a channel 31!). The parts are soproportioned that the channel 311) receives either of the ridges 26a or26b of the bit 26, to be sharpened. It is shown in Figures 8, 9 and 10as clamped by a clamping lever 32 which may be pivoted, as at 33, to orbetween webs 34 of the carrier 30. It may be urged toward lockingposition, for example, by the bolt 35, the head of which is receivedbetween flanges 36 extending rearwardly from the lever 32. Any suitablemeans, such as the thumb nut 37, may be employed for locking the 3 bolt35 with the parts in locking position, the bolt passing through anysuitable aperture 38 in the guiding flange 31. 40 indicates a stophaving an inclined face 41 to receive the end ofthe bit 26. Thus the bitmay readily be clamped inposition in a predetermined relationshipbetween the end, of the bit and the grinding wheel 10, as shown inFigure9. In this position it may then be urged against the side of thegrinding Wheel 10 in order to cut the lateral indentation 260 or 26dwhich completes the cutting-edge of the tool: or bit, as shown in Figure11.

Itwillbe realized that whereas I have described and shown a practicaland operative device, nevertheless many changes may be madein size,shape, number and disposition of parts without departing from the spiritof my invention. I therefore wish, my description and drawings to betaken as in a broad sense illustrative or diagrammatic, rather than. aslimiting me to my specific disclosure herein. It will be understood, forexample, that v whereas I illustrate a structure adapted for apredetermined sharpening or forming of a particular tool or bit, mystructure may by slight changes be adapted to-operate for the sharpeningsurfaces or grinding of a variety of bits or tools.

The use and operation of my invention are as follows:

I provide a readily portable, easily handled unit, which includes asmall motor and at least one grinding disk or wheel driven thereby. Thesupports 15 and 18, as shown in Figures 1 and 2, can be adjusted towardand away from the cutting path of the grinder. Thus grinder wear orchanges in size of grinding disks can be compensated for.

The three rollers or wheels 19, 20 and 21 constitute a three-pointsupport for a carrier. I illustrate two carriers, each designed andformed to present a bit or tool for movement along a predetermined pathtoward the cutter. The carrier is traversed along a predetermined pathguided or controlled by the three rollers. Taking first the use of thecarrier 25, the screw 27 constitutes an outward positioning abutmentwhich. may be adjusted, at the desire of the operator, toreceive theouter end of the bit. Assuming that the tools or bits as they come fromstock are all of a uniform length, the abutment or positioning screw 27would be located in a relatively Withdrawn position. But if used toolsor bits are being resharpened, the abutment can be adjusted to anydesired position to take the initially shorter bits. Since the bit ortool itself has positioning ribs, it is readily guided by correspondingguiding channels in the carrier.

Where it is desired to present the bit to the grinder from a difierentangle, to side-grind the surfaces 26c and 26d, I employ the carrier 30.Here again the bit is positioned by a channel 31b which guides orcontrols the position or angle of the bit in relation to the grinder. Inthe use of the carrier 30, as shown for example in Figure 9, the bit isfed against the forward abutment or stop 40, 41,

which limits the movement of the bit into the path of the cutting wheel10. The bit is then moved laterally against the cutting wheel, bytraversing the carrier, to cut the surface 260 or 26d. The rollers 19,20 and 21 are preferably provided with any suitable anti-frictionalbearings, so that a minimum of force is required to traverse thecarriers. This is done manually and can be done very quickly. Asubstantial number of bits can be sharpened or ground in sequence.

I claim:

In a grinding assembly for drill bits and the like, a base and agrinding wheel mounted on said base for rotation about a predeterminedaxis, motor means on said base for rotating said grinding wheel, saidbase including spaced sleeves extending generally perpendicularly to theaxis of said grinding wheel, a pair of rods inserted in said sleeves andmeans for holding said rods within said sleeves, a guiding supportjoined to said rods. andextending in front of said grinding wheel, saidguiding support including spaced roller elements journaled for rotationabout axes generally parallel to the axes of said sleeves, a bitcarriage having downwardly extending guide track means engageable withsaid rollers for movement of the carriage along a line generallyparallel to the axis of said wheel, said carriage being removable fromsaid rollers upon upward movement therefrom, said carriage including anupstanding portion with, a substantially plane guiding surface, theplane of said surface extending generally parallel to the axes of saidrods, said guiding surface having a channel formed therein. forreceiving the ridge of abit positioned against said surface, anadjustable clamping lever on the carriage and cooperable with saidsurface for clamping a bit therebetween, and a, stop on said car,- riagebetween said wheel and said carriage, said stop being in the path of abit positioned against said surface but spaced from the axis of saidchannel, movement of said carriage along said rollers being efiective.to force said bit against the side of said wheel.

References Cited in the file of this patent UNITED STATES PATENTS523,897 Kenyon July 31, 1894 981,810 Sterling Jan. 17, 1911 1,101,593Wagner June 30, 1914 1,110,366 Wincrantz Sept. 15, 1914 1,522,465 KimmelJan. 6, 1925 1,539,829 Cole June 2, 1925 1,915,247 Holloway et al June20, 1 933 2,083,682 Balsiger et al June 15, 1 937 2,087,304 Sawyer July20, 1937 2,460,491 Cooke Feb. 1, 1949 2,536,823 Smith Jan. 2, 19512,619,779 Kristenson Dec. 2, 1952

